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Globular cluster populations in Coma ultra di ff use galaxies - - PowerPoint PPT Presentation

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Stellar halos across the cosmos July 2-6, 2018, Heidelberg Globular cluster populations in Coma ultra di ff use galaxies Sungsoon Lim Peking University, China Collaborators: Eric W. Peng (Peking University, China) Patrick Cote

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SLIDE 1

Globular cluster populations 
 in Coma ultra diffuse galaxies

Sungsoon Lim 


Peking University, China

Collaborators: Eric W. Peng (Peking University, China)
 Patrick Cote (National Research Council of Canada) Laura V. Sales (UC Riverside) Mark den Brok (AIP , Potsdam) John P . Blakeslee (Gemini Observatory)
 Puragra Guhathakurta (UC Santa Cruz)

“Stellar halos across the cosmos” July 2-6, 2018, Heidelberg (Lim et al. 2018 ApJ accepted
 arXiv:1806.05425)

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SLIDE 2

UDGs are everywhere

  • Forty seven UDGs in the Coma cluster


(van Dokkum et al. 2015)

  • Five UDGs in the Virgo cluster 


(Mihos et al. 2015; Beasley et al. 2016; Mihos et al. 2017)

  • Several UDGs in the Fornax cluster


(Muñoz et al. 2015)

  • About 300 UDGs in the Coma cluster 


(Koda et al. 2015; Yagi et al. 2016)

  • Many UDGs in other galaxy clusters


(e.g. van der Burg et al. 2016; 
 Janssens et al. 2017; Lee et al. 2017)

  • UDGs in less dense environments 


(Martínez-Delgado et al. 2016; 
 Roman & Trujillo 2016a)

(UDGs in the Virgo; Mihos et al. 2015) (DF44 in the Coma; 
 van Dokkum et al. 2015,2016,2107) (DF4 in M101; 
 Merritt et al. 2016)

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SLIDE 3

Globular Clusters

  • A good tracer of stellar

population

  • GC specific frequency (SN):


Number of GCs per unit luminosity of host galaxy

  • Empirical relation between 


total number of GCs and total mass

(ACSVCS; Peng et al. 2008)

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SLIDE 4

Globular Clusters

  • A good tracer of stellar

population

  • GC specific frequency (SN):


Number of GCs per unit luminosity of host galaxy

  • Empirical relation between 


total number of GCs and total mass

(Harris et al. 2013)

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SLIDE 5

GCs in UDGs

  • Large GC population in

DF17 (Peng & Lim 2016)

  • Large GC populations in 


VLSB-B, VLSB-D,VCC 615 


(Mihos et al. 2015, 2018; 
 Toloba, Lim et al 2018)


DF44, DFX1 


(van Dokkum et al. 2017)

  • UDG may also follow the

relation between 
 NGC & Mtotal.

(Peng & Lim 2016)

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SLIDE 6

GCs in UDGs

  • Large GC population in

DF17 (Peng & Lim 2016)

  • Large GC populations in 


VLSB-B, VLSB-D,VCC 615 


(Mihos et al. 2015, 2018; 
 Toloba, Lim et al 2018)


DF44, DFX1 


(van Dokkum et al. 2017)

  • UDG may also follow the

relation between 
 NGC & Mtotal.

(Toloba, Lim et al. 2018)

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SLIDE 7

More GC studies

  • GCs of ~15 UDGs in Coma

cluster central region using Coma Treasury Survey


  • van Dokkum et al. 


(2017,+3 additional UDGs); 


  • Amorisco et al.(2018)



 
 
 
 


(van Dokkum et al. 2017) (Amorisco et al. 2018)

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SLIDE 8

More GC studies

  • GCs of ~15 UDGs in Coma

cluster central region using Coma Treasury Survey


  • van Dokkum et al. 


(2017,+3 additional UDGs); 


  • Amorisco et al.(2018)



 
 
 
 


(van Dokkum et al. 2017)

(van Dokkum et al. 2015)

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SLIDE 9

More GC studies

  • GCs of ~15 UDGs in Coma

cluster central region using Coma Treasury Survey


  • van Dokkum et al. 


(2017,+3 additional UDGs); 


  • Amorisco et al.(2018)



 
 
 
 


(van Dokkum et al. 2017)

(van Dokkum et al. 2015)

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SLIDE 10

More GC studies

  • GCs of ~15 UDGs in Coma

cluster central region using Coma Treasury Survey


  • van Dokkum et al. 


(2017,+3 additional UDGs); 


  • Amorisco et al.(2018)



 
 
 
 


(van Dokkum et al. 2017)

(van Dokkum et al. 2015)

Most UDG GC studies cover small number of UDGs or small area of the galaxy cluster. To explore UDG formation, we need a systematic GC study of UDGs over a large area of the cluster

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SLIDE 11

Targets &
 Observation

  • 34 UDGs 


(our HST program - 
 26 orbits of HST ACS/WFC PID:14658; PI: Eric Peng
 + DF17, Peng & Lim 2016)

  • 14 UDGs 


(in Coma Treasury survey 
 + DF42, DF44, DFX1; 


van Dokkum et al. 2017)

  • classical dwarfs in Coma

Treasury survey 


(den Brok et al. 2014)

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SLIDE 12

Targets &
 Observation

  • 34 UDGs 


(our HST program - 
 26 orbits of HST ACS/WFC PID:14658; PI: Eric Peng
 + DF17, Peng & Lim 2016)

  • 14 UDGs 


(in Coma Treasury survey 
 + DF42, DF44, DFX1; 


van Dokkum et al. 2017)

  • classical dwarfs in Coma

Treasury survey 


(den Brok et al. 2014)

slide-13
SLIDE 13

Targets &
 Observation

  • 34 UDGs 


(our HST program - 
 26 orbits of HST ACS/WFC PID:14658; PI: Eric Peng
 + DF17, Peng & Lim 2016)

  • 14 UDGs 


(in Coma Treasury survey 
 + DF42, DF44, DFX1; 


van Dokkum et al. 2017)

  • classical dwarfs in Coma

Treasury survey 


(den Brok et al. 2014)

(van Dokkum et al. 2015)

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SLIDE 14

Targets &
 Observation

  • 34 UDGs 


(our HST program - 
 26 orbits of HST ACS/WFC PID:14658; PI: Eric Peng
 + DF17, Peng & Lim 2016)

  • 14 UDGs 


(in Coma Treasury survey 
 + DF42, DF44, DFX1; 


van Dokkum et al. 2017)

  • classical dwarfs in Coma

Treasury survey 


(den Brok et al. 2014)

(van Dokkum et al. 2015)

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SLIDE 15

Targets &
 Observation

  • 34 UDGs 


(our HST program - 
 26 orbits of HST ACS/WFC PID:14658; PI: Eric Peng
 + DF17, Peng & Lim 2016)

  • 14 UDGs 


(in Coma Treasury survey 
 + DF42, DF44, DFX1; 


van Dokkum et al. 2017)

  • classical dwarfs in Coma

Treasury survey 


(den Brok et al. 2014)

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SLIDE 16

Targets &
 Observation

  • 34 UDGs 


(our HST program - 
 26 orbits of HST ACS/WFC PID:14658; PI: Eric Peng
 + DF17, Peng & Lim 2016)

  • 14 UDGs 


(in Coma Treasury survey 
 + DF42, DF44, DFX1; 


van Dokkum et al. 2017)

  • classical dwarfs in Coma

Treasury survey 


(den Brok et al. 2014)

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SLIDE 17

GC Specific Frequency (SN)

  • SN of UDGs varies a

lot.

  • UDGs have higher SN

than those of normal dwarfs.

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SLIDE 18

GC Specific Frequency (SN)

  • SN of UDGs varies a

lot.

  • UDGs have higher SN

than those of normal dwarfs.

Mean SN of 
 classical dwarf galaxies
 in Coma

SN 1σ

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SLIDE 19

GC Specific Frequency (SN)

  • SN of UDGs varies a

lot.

  • UDGs have higher SN

than those of normal dwarfs.

Mean SN of 
 classical dwarf galaxies
 in Coma

SN 1σ

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SLIDE 20

GC SN connection to the galaxy size

  • Mean SN value increases

with galaxy size.

  • This trend is getting

weaker at faint UDGs.

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SLIDE 21

GC SN connection to Environments

The mean SN to be higher at the cluster center and lower in the outskirts.

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SLIDE 22

Rapid quenching of SF 
 in the dense environment

  • In Liu et al. (2016)


(Liu et al. 2016)

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SLIDE 23

GC

High density Rapid quenching Low density Gradual quenching Young galaxies in
 the Early Universe Old galaxies today

GC Gas Stars

Same final stellar masses Different initial total (gas) masses

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SLIDE 24

Origin of massive UDGs?

  • Mean total mass of high SN UDGs 


~ total mass of M33

  • Mean stellar mass of high SN UDGs 


~ 5% stellar mass of M33

  • Based on SFH of M33, 5% of current

mass of M33 were formed about 7 Gyr ago (Barker et al. 2011).

  • Above results suggest that M33 size

galaxies fell into the Coma clusters about 7 Gyr ago, and their star formation was quenched, and eventually became High SN UDGs

  • Some UDGs have mean stellar ages
  • f 7-9 Gyr (Gu et al. 2018; Ferre-

Mateu et al. 2018; Ruiz=Lara et al. 2018).

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SLIDE 25

Origin of massive UDGs?

  • Mean total mass of high SN UDGs 


~ total mass of M33

  • Mean stellar mass of high SN UDGs 


~ 5% stellar mass of M33

  • Based on SFH of M33, 5% of current

mass of M33 were formed about 7 Gyr ago (Barker et al. 2011).

  • Above results suggest that M33 size

galaxies fell into the Coma clusters about 7 Gyr ago, and their star formation was quenched, and eventually became High SN UDGs

  • Some UDGs have mean stellar ages
  • f 7-9 Gyr (Gu et al. 2018; Ferre-

Mateu et al. 2018; Ruiz=Lara et al. 2018).

~Mtotal of M33

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SLIDE 26

Origin of massive UDGs?

  • Mean total mass of high SN UDGs 


~ total mass of M33

  • Mean stellar mass of high SN UDGs 


~ 5% stellar mass of M33

  • Based on SFH of M33, 5% of current

mass of M33 were formed about 7 Gyr ago (Barker et al. 2011).

  • Above results suggest that M33 size

galaxies fell into the Coma clusters about 7 Gyr ago, and their star formation was quenched, and eventually became High SN UDGs

  • Some UDGs have mean stellar ages
  • f 7-9 Gyr (Gu et al. 2018; Ferre-

Mateu et al. 2018; Ruiz=Lara et al. 2018).

~Mtotal of M33 ~5%Mstar of M33

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SLIDE 27

Origin of massive UDGs?

  • Mean total mass of high SN UDGs 


~ total mass of M33

  • Mean stellar mass of high SN UDGs 


~ 5% stellar mass of M33

  • Based on SFH of M33, 5% of current

mass of M33 were formed about 7 Gyr ago (Barker et al. 2011).

  • Above results suggest that M33 size

galaxies fell into the Coma clusters about 7 Gyr ago, and their star formation was quenched, and eventually became High SN UDGs

  • Some UDGs have mean stellar ages
  • f 7-9 Gyr (Gu et al. 2018; Ferre-

Mateu et al. 2018; Ruiz=Lara et al. 2018).

~Mtotal of M33 ~5%Mstar of M33

SFH of M33 (Barker et al. 2011)

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SLIDE 28

Origin of less massive UDGs?

  • Their M/L ratio is similar to classical

dwarf galaxies.

  • Following scenarios can explain dwarf
  • rigin UDGs:

  • Large angular momentum (or spin) of

dwarf galaxies 


(Amorisco & Loeb 2016; Rong et al. 2017); 


  • DM and stellar expansion of normal

dwarf galaxies by feedback driven gas

  • utflow


(Di Cintio et al. 2017; Andrew’s talk); 


  • Tidal effects by environments


(Collins et al. 2013; Carleton et al. 2018)

  • Low SN UDGs are more elongated than

high SN UDGs.


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SLIDE 29

Origin of less massive UDGs?

  • Their M/L ratio is similar to classical

dwarf galaxies.

  • Following scenarios can explain dwarf
  • rigin UDGs:

  • Large angular momentum (or spin) of

dwarf galaxies 


(Amorisco & Loeb 2016; Rong et al. 2017); 


  • DM and stellar expansion of normal

dwarf galaxies by feedback driven gas

  • utflow


(Di Cintio et al. 2017; Andrew’s talk); 


  • Tidal effects by environments


(Collins et al. 2013; Carleton et al. 2018)

  • Low SN UDGs are more elongated than

high SN UDGs.


Round Elongated

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SLIDE 30

Multiple channels of 
 UDG formation

  • Inefficient star formation
  • f massive galaxies in

dense environments

  • Large angular

momentum (or spin) of dwarf galaxies; DM and stellar expansion of normal dwarf galaxies by feedback driven gas

  • utflow; or tidal effects

by environments


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SLIDE 31

UDGs with Nucleus

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SLIDE 32

UDGs with Nucleus

(Ordenes-Briceno et al. 2018)

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SLIDE 33

Summary

  • We studied GCSs of 48

UDGs in the Coma cluster.

  • GC Specific frequency

varies a lot among UDGs.

  • We found the environmental

dependence of GC specific frequency with large scatters.

  • Our results suggest multiple

formation mechanisms for UDGs.

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SLIDE 34

Summary

  • We studied GCSs of 48

UDGs in the Coma cluster.

  • GC Specific frequency

varies a lot among UDGs.

  • We found the environmental

dependence of GC specific frequency with large scatters.

  • Our results suggest multiple

formation mechanisms for UDGs.

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SLIDE 35

Summary

  • We studied GCSs of 48

UDGs in the Coma cluster.

  • GC Specific frequency

varies a lot among UDGs.

  • We found the environmental

dependence of GC specific frequency with large scatters.

  • Our results suggest multiple

formation mechanisms for UDGs.

(Lim et al. 2018 
 arXiv:1806.05425)